Scilab Function
Last update : 20/12/2004

zpbutt - Butterworth analog filter

### Calling Sequence

  `[pols,gain]=zpbutt(n,omegac)`

### Parameters

- `n`: integer (filter order)
- `omegac`: real (cut-off frequency in Hertz)
- `pols`: resulting poles of filter
- `gain`: resulting gain of filter

### Description

computes the poles of a Butterworth analog filter of order `n` and cutoff frequency omegac transfer function H(s) is calculated by `H(s)=gain/real(poly(pols,'s'))`

### Author

F. Delebecque INRIA